The present invention relates to a printing apparatus and a method of printing, wherein the printing apparatus includes a media defect detection system for detecting defects on media and controlling subsequent printing on the media.
During the manufacture of media such as photographic paper, defects can occur on the media. Manufactured media can be inspected on a master roll before it is slit into finished rolls at a manufacturing site and can be manually inspected at a photofinishing or printing site.
Typically, media such as color paper rolls with defects that meet a certain size criteria as detected at the manufacturing site are discarded and not passed on to the photofinisher. Large-scale photofinishers can utilize 4 inch by 1800-foot rolls and can be quite inflexible on variations in roll length. The effect of this combination means that when a single defect falls within a customer roll, the entire customer roll may be discarded as waste since the defect in the media will show up on a completed print, resulting in a defective image. All other prints of the roll may be acceptable. In addition, some media defects can be of a characteristic that will not be noticeable in a finished print, potentially making all prints of that roll acceptable. Therefore, discarding an entire customer roll due to certain defects leads to waste of media.
If the defects are not detected at the manufacturing site, they will have to be detected at a photofinishing site. Typically, a manual inspection occurs at the photofinishing site. This inspection is time consuming, inefficient, and depends on the skill of an operator.
The system and apparatus of the present invention reduces unnecessary waste by precisely locating media defects and either not printing the media frames associated with those defects or identifying the prints made on those frames for rejection and making replacement prints on clean media. This prevents an entire customer roll from being discarded when a single defect is found in that roll during manufacturing. Thereafter, printing is controlled by preventing the defect from getting onto a print or by remaking the defective print.
The present invention provides for a printer or printing apparatus, which is interfaced with a defect detection system capable of precisely identifying a defect and the location of the defect on the media. With the printer of the present invention, manufactured media can be forwarded to a photofinishing site without discarding media with defects thereon. The printer of the present invention is capable of scanning the media to detect defects of a particular characteristic and providing for a physical mark on the media in close proximity of the noted defect or electronically reporting the precise location of the defect. The printer is thereby instructed to either skip over the defect frames or reprint the image frames upon which the defects will fall. In the embodiment of the invention as described above, the printer is interfaced with the defect scanning system and a defect marker or signaling device. In a further variation of the present invention, the scanning system can be off-line on a separate conveying system (i.e., a rewinder), and mark the position of the defect, so that the printer can detect it.
A preferred method of marking the location of the defect on the media involves marking it by way of a punch to form a hole in the center of the media just ahead of where the defect is located. With this approach, the printer will skip the hole and defect frames similarly to the way it skips splice frames marked with a hole. This center hole is not to be confused with the punched holes that can be at other locations on the media.
The present invention therefore provides for a printing apparatus which comprises a defect scanning section for scanning unexposed media in a media path in the printing apparatus to detect defects of a predetermined characteristic on the media; a defect marker located downstream of the defect scanning section with respect to a direction of travel of the media in the printing apparatus, with the defect marker receiving a signal from the defect scanning section indicative of a defect in the media and placing a physical mark on the media near the detected defect, such that the physical mark is associated with an image frame carrying the defect; and a printing section for printing images on the media, with the printing section being able to scan the media for the physical marks and skip the frames of the media which include the physical marks and their associated defects, such that the printing section prints images on only those frames which have no defects or physical marks.
The present invention further provides for a printing apparatus that comprises a defect scanning section for scanning unexposed media in a media path of the printing apparatus, to detect defects of a predetermined characteristic on the media; a defect marker located downstream of the defect scanning section with respect to a direction of travel of the media in the printing section, with the defect marker receiving a signal from the defect scanning section indicative of a defect in the media and placing a physical mark on the media near the detected defect, such that the physical mark is associated with an image frame carrying the defect; and a printing section for printing images on the media, with the printing section being adapted to scan the media for the physical marks and print images on the image frames, wherein images printed in frames having the physical marks and their associated defects are reprinted on defect-free media and the defective prints are discarded.
The present invention further relates to a method of printing images on media which comprises the steps of scanning media to detect a precise location of defects of a predetermined characteristic on the media; transmitting information with respect to the detected defects electronically to a printing section of a printer; and using the information to control subsequent printing of images by the printer on the media by skipping frames with the defects and printing images on defect-free media.
The present invention further relates to a method of printing images on media which comprises the steps of scanning media to detect a precise location of defects of a predetermined characteristic on the media; transmitting information with respect to the detected defects electronically to a printing section of a printer; and using the information to reprint those images which are printed on frames having defects, while tracking and discarding the prints with defects thereon.